Shatapatha Brahmana 11.4.2.1

11.4.2.1

athātaḥ srucorādānasya taddhaitadeke kuśalā manyamānā dakṣiṇenaiva juhūmādadate savyenopabhṛtaṃ na tathā kuryādyo hainaṃ tatra brūyātpratipratiṃ nvā ayamadhvaryuryajamānasya dviṣantam bhrātṛvyamakatpratyudyāminamitīśvaro ha tathaiva syāt

Now, then, as to the taking up of the two offering-spoons. Now, in this respect, some people, thinking themselves clever, take up the (guhû) with the right, and the upabhrit with the left (hand); but let him not do so; for if, in that case, any one were to say of him, 'Surely, this Adhvaryu has made the Sacrificer's spiteful enemy equal to him, and able to cope with him,' then that would indeed be likely to come to pass.